1. Field of the Invention
The invention relates to an apparatus for the production of molded concrete parts.
2. Description of the Related Art
Apparatuses for the production of molded concrete parts, such as paving bricks, for example, are typically used for machine production and contain a molding machine having a punch unit and a lower mold part configured as a mold, into which the punch unit can engage. Usually, one mold insert is or a number of mold inserts are configured in the lower mold part, whose cavities are open toward the top and the bottom. The lower mold part is set onto a horizontal bed with a lower delimitation plane of a brick field, which bed closes off the lower openings of the mold. The mold inserts are filled with concrete mixture through the upper openings; this mixture is subsequently pressed by way of pressure plates disposed on the punch unit, in that the pressure plates are lowered into the mold inserts through the upper openings. Subsequently, solidification of the concrete mixture to form shape-stable molded concrete parts takes place by means of shaking, typically of the bed. The parts are unmolded through the lower openings of the mold inserts.
The punch unit is connected with a vertical movement unit of the molding machine, which unit is typically hydraulically activated, and can be displaced vertically by means of this unit. The connection can be made, in a conventional design, by way of a top-load unit, which, together with the punch unit, usually forms an upper mold part as a module that can be handled as one part. A uniform brick height is achieved even with different compaction of the concrete mixture, by means of a stop on the punches of the punch unit.
In the design of such apparatuses for the production of molded concrete parts, attachment of the punch unit to the upper mold part and to the pressure plates has particular significance, because this attachment must allow positioning of the punches and stable support of the punches against forces that act in tilting and/or twisting manner.
From the general state of the art, apparatuses are known in which a punch is connected, by means of a welded connection, with a screw-on plate onto which a pressure plate is screwed, for easier replacement.
Thus, the production of compacted molded concrete bricks is described, for example in DE 10302693 B3. This production typically takes place in molding machines, in which a mold that lies on a shaker bed and has one or more mold inserts is filled with concrete mass. Pressure plates are introduced into the mold inserts from above; these plates are attached by vertical punches at lower ends. At their upper ends, the punches are welded to a punch carrier, usually a stable plate. The punch carrier is pressed downward during the shaping process, by way of a machine connection.